Service diversity for communication system

ABSTRACT

A communication transaction or use case is broken down into constituent parts, one of which can be provided, at the direction of a master service node, from the master service node or primary service path and the other of which can be provided from a support service node or secondary service path that the client station might happen to be able to communicate with. For instance, the base layer of a multimedia stream might be provided from the master node, but if its bandwidth becomes full, an enhancement layer of the stream can be provided by the support node, as directed by the master node.

FIELD OF THE INVENTION

[0001] The present invention relates generally to computer-basedcommunication systems.

BACKGROUND

[0002] Nodes such as server platforms, client stations, peer stations,and intermediate station nodes in current communication systemstypically must select a single channel or single link or othercommunication interface incident to undertaking a data transfertransaction or a so-called “use case” (essentially, one or moretransactions or constituent use cases directed to a common goal), suchas the wireless transmission of multimedia data or the downloading of aWeb page. This is so even though the nodes themselves might be capableof communicating over a number of diverse channels or links. Service istypically provided over the single channel or link from a single server.

[0003] A service provider, either as server or peer, serving a group ofclients or peers with multi-channel/multi-link capabilities establishesconnections, assigns resources, and otherwise engages in utilizingfinite capacities to serve those clients or peers on an “as come” basis.Such allocation often causes ineffective and/or inefficient use of theoverall system resources and capabilities as clients or peers engage anddisengage services stochastically. For example, a multicast routerallocates link utilization based on the shortest route as multicastmembers engage in a multicast from various point on the global Internet.As time progresses, the router may experience increasing queuing delayon one or more links, while other available links have availablecapacity to be used.

[0004] Currently, this problem is addressed using what can be thought ofas the law of large numbers, which entails reliance on low probabilityevents consuming no more than, say, 5% of the total service time whereinthe ineffective/inefficient utilization is of significant impact tooverall system performance. Such approaches take advantage of the largenumber of independent arrivals and departures of service requestsrelative to the capacity of the single resource being used. For example,backbone routers may handle 10⁵ connections at any moment in time on asingle link. These connections are engaged and disengaged at a rate of100 per second, and last on the order of 10 seconds each, leavingsufficient room for the law of large numbers to provide a comfortablemargin.

[0005] In the case of providing many types of newer services, however,the present invention recognizes that the above-discussed “law of largenumbers” can break down. For instance, providing several wireless clientstations with multimedia content typically requires high bandwidth sincea great deal of data transmission is entailed, and moreover clientstypically remain connected for a substantial period, instead ofconnecting and disconnecting relatively rapidly as is the case for anordinary telephone call. Unfortunately the server, a wirelesscommunication system base station in this case, has finite transmissionbandwidth. It might be able to provide all client stations within itsgeographic area with a base level of service, e.g., the base stationmight have the bandwidth to supply all nearby client stations with thebase layer of a multimedia stream, but it might not have sufficientbandwidth, depending on the circumstances, to provide all clientstations with enhancement layers of the stream. An adjacent base stationmight happen to have spare bandwidth at that moment, but even if some ofthe client devices are close enough to it to receive data from theadjacent base station, present protocols permit only the transfer of theentire service between base stations. They do not permit load sharingamong base stations to deliver different parts of the same servicesimultaneously. Having made these critical observations, the inventiondisclosed herein is provided.

SUMMARY OF THE INVENTION

[0006] A transaction or use case makes use of a procedure and a protocol(both as programmatic interface and information stream structure) suchthat altering the underlying resource allocation that serves thetransaction or use case is easily accommodated without any discontinuityof service.

[0007] With more specificity, a communication system includes first andsecond service nodes and a client station positioned to communicate withthe service nodes over respective first and second channels. The firstservice node provides a first part of a use case to the client stationand the second service node provides a second part of the use case tothe client station simultaneously with the provision of the first partby the first service node. The first and second parts do not representthe same data as each other.

[0008] In one non-limiting example, the first part is a base layer of amultimedia stream and the second part is an enhancement layer of themultimedia stream that is associated with the base layer. The clientstation overlays the enhancement layer onto the base layer to establishframes of the multimedia stream, with each frame including data from thebase layer and data from at least one enhancement layer. The channelscan be bidirectional.

[0009] In another aspect, a method for communication of a single usecase to a client station from a service system having at least first andsecond service resources includes communicating a first part of the usecase using the first service resource to the client station, anddetermining whether to direct the client station to receive a secondpart of the use case from the second service resource. The first andsecond parts are different from each other in that the second part isnot merely duplicative of the first part. The method also includesselectively directing the client station to receive the second part fromthe second service resource.

[0010] In the preferred method, the first and second parts can bereceived over respective first and second links. In someimplementations, the first service resource is a first server and thesecond service resource is a second server. In a specific non-limitingembodiment, the first server is a first wireless communication systembase station and the second server is a second base station. In thisembodiment, the first part can be a base layer of a multimedia streamand the second part can be an enhancement layer of the multimediastream. The multimedia stream can be digitally broadcast. In anotherimplementation, the first service resource is a first trunk line and thesecond service resource is a second trunk line. In still anotherimplementation, the first service resource is a satellite providing abase layer of a multimedia stream and the second service resource is aterrestrial resource providing an enhancement layer of the multimediastream.

[0011] In still another aspect, a client station has a first receiverreceiving a first part of a use case from a first service resource and asecond receiver receiving a second part of the use case from a secondresource.

[0012] The details of the present invention, both as to its structureand operation, can best be understood in reference to the accompanyingdrawings, in which like reference numerals refer to like parts, and inwhich:

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a block diagram of a simplified system; and

[0014]FIG. 2 is a flow chart of the present process.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0015] Referring initially to FIG. 1, a system is shown, generallydesignated 10, that includes plural nodes, such as a first server 12 anda client station 14, although the nodes can be peers in the system 10.The first server 12 has a processor 16 and the client station 14 has aprocessor 18 for undertaking the communication logic disclosed herein.Also, a second server 19 can establish a node of the system. In onenon-limiting exemplary embodiment, the servers 12, 19 might be wirelesscommunication system base stations (BTS). In other embodiments, one orboth servers might be routers.

[0016] Also, as shown the client station 14 includes at least first andsecond communication systems 20, 22 for respectively communicating withthe servers 12, 19 over respective first and second channels or links24, 26. That is, the communication systems 20, 22 are configured forcommunicating over the respective links 24, 26. Thus, if the link 24 isa satellite link, the communication system 20 is a satellitecommunication system. On the other hand, if the link 26 is a wirelesspoint-to-point link, the communication system 22 is a wirelesspoint-to-point system such as CDMA or GSM. The links 24, 26 (andrespective communication systems 20, 22 in the client station 14) may bethe same as each other or different from each other. For instance, whenone of the servers 12, 19 is a router, the links 24, 26 can be trunklines. The client station 14 can include additional or differentcommunication systems, such as a 802.11 communication system.

[0017] The channels or links 24, 26 may have different class of service(COS) characteristics. For example, the first link 24 can have a higheror lower bandwidth than the second link 26, and/or more or less latency,and/or greater or lesser error quality characteristics, and/or otherdifferent COS variables. Non-limiting examples of the types of links orchannels to which the invention applies includes wireless communicationpoint-to-point links, UHF/VHF/SHF/EHF broadcast links, landlinebroadcast links, infrared (IR) links, ethernet links, 802.11 type links,satellite links, etc. A particular COS can be thought of as a class oflinks that fulfill the service requirements of an application orprotocol. Each link 24, 26 may be composed of a receive frequency and adifferent, transmit frequency.

[0018] In one non-limiting embodiment, the client station 14 can be a“mobile station (“MS”), such as a mobile telephone-type device made byKyocera, Samsung, or other manufacturer that uses Code Division MultipleAccess (CDMA) principles and CDMA over-the-air (OTA) communication airinterface protocols such as defined in but not limited to IS-95A,IS-95B, WCDMA, IS-2000, and others to communicate with wirelessinfrastructure, although the present invention applies to GSM, PersonalCommunications Service (PCS) and cellular systems, such as AdvancedMobile Phone System (AMPS) and the following digital systems: CDMA, TimeDivision Multiple Access (TDMA), and hybrid systems that use both TDMAand CDMA technologies. A CDMA cellular system is described in theTelecommunications Industry Association/Electronic IndustriesAssociation (TIA/EIA) Standard IS-95. Combined AMPS and CDMA systems aredescribed in TIA/EIA Standard IS-95. Other communications systems aredescribed in the International Mobile Telecommunications System2000/Universal Mobile Telecommunications Systems (IMT-2000/UM),standards covering what are referred to as wideband CDMA (WCDMA),cdma2000 (such as cdma2000 1× or 3× air interface standards, forexample) or TD-SCDMA.

[0019] The client station 14 may also be a computer that wirelesslyaccess the Internet and/or that access the Internet through a landline.

[0020] The process of the present invention can be appreciated inreference to FIG. 2, which can be undertaken using a computer.Commencing at block 27 and assuming that the first server 12 is theserver primarily responsible for providing a particular use case to theclient station 14, the server 12 identifies an alternate source orserver or other service provisioning resource for at least parts of theuse case. For example, if the server 12 is a router that intends toroute communication to the client station 14 over the first link 24 (inthis case, a first trunk line), the server 12 might identify the secondlink 26 as being a second trunk line over which parts of the use casepotentially could be provided. Or, if the server 12 is a wirelesscommunication system BTS providing a digital broadcast multimedia streamto the client station 14 over the first link 24, the server 12 mightidentify the second server 19 as a BTS that is sufficiently close to theclient station 14 that it can provide portions of the multimedia streamto the client station 14 over the second (in this case, wireless) link26.

[0021] Proceeding to block 28, potentially separable parts of the usecase are identified. In the context of digital broadcast media, forexample, it might be identified that the multimedia stream includes abase layer and one or more enhancement layers. More specifically, somedelta prediction schemes such as MPEG4 allow for so-called “enhancementlayers” of bits during quantization. Essentially, a “base layer” isprovided for each frame for each stream that represents a minimum amountof data necessary to render the frame, with enhancement layers for theframe being available to add fidelity to the image or sound provided bythe base layer. The benefit provided by the increased bit rate resultingfrom the addition of the enhancement layers can be indicated along withthe enhancement layers themselves.

[0022] In any case, it is to be appreciated that the different partsthat are identified at block 28 are not mere duplicates of each other,in contrast to, e.g., transmitting the same wireless data from two basestations to a single wireless receiver to ensure reception of the data.Rather, the first and second part are different parts of the same usecase/transaction.

[0023] Proceeding to block 30, the capabilities of the client station 14are determined, to determine whether the client would be able to receiveparts of the use case over both links 24, 26. Assuming it can, the logicproceeds to block 32, wherein the server 12 periodically informs theclient station 14 to stand by to receive parts of the use case from thealternate source/server. The server 12 may also periodically check thealternate source/server to ensure that it remains available.

[0024] In accordance with the present invention, the logic next flows todecision diamond 34, wherein the server 12 determines whether it is at alimit of capacity that requires switching provisioning of parts of theuse case to the alternate source/server. When the threshold is reached,the logic moves to block 36, wherein the server 12 directs the clientstation 14 to receive part of the use case from the alternatesource/server. For example, in the context of wireless digitalmultimedia, at block 36 the client station 12 might receive a base layerof the multimedia stream from the first server 12 (in this, a primaryBTS) and simultaneously receive one or more enhancement layers of thesame stream from the second server 19 (in this case, a secondary BTSthat is sufficiently close to the client station 14 to serve it). In anycase, at block 38 the client station 14 combines the parts. For example,in the case of the above-discussed multimedia application, at block 38the client station 14 would overlay the enhancement layer onto the baselayer in accordance with principles known in the art.

[0025] As another example, consider a multi-mode mobile multimediaclient station device 14 with a terrestrial IxEv-DO link and a L/S/Cband Low Earth Orbit (LEO) satellite link. The service provider canbroadcast a multimedia base layer over the geographically broader LEOsatellite downlink such that all devices within the geographic coverageof the LEO downlink can receive this layer and thus render a basequality of the broadcast media. However, clients desiring additionalquality can receive enhancement layers of the multimedia stream over theterrestrial broadcast link. The service provider may choose to limit lowcount clients of a given cell when bandwidth resources are not availablewithin that cell. The advantage of this use of multiple channelsincludes reduced bandwidth utilization by many base stations of the samemultimedia material and therefore a greater availability of bandwidthfor the enhancement layers.

[0026] In still another example, the client station 14 may use an RFreceiver capable of multiple channel selections, each of which couldestablish a respective link, e.g., the links 24, 26. Each link isunidirectional. The client station 14 may be directed to obtain oneportion of a use case on a first channel and obtain the other portionsof the use case on a second channel. The client station 14 can tunetransmitting channels independently of receiving channels.

[0027] While the particular SERVICE DIVERSITY FOR COMMUNICATION SYSTEMas herein shown and described in detail is fully capable of attainingthe above-described objects of the invention, it is to be understoodthat it is the presently preferred embodiment of the present inventionand is thus representative of the subject matter which is broadlycontemplated by the present invention, that the scope of the presentinvention fully encompasses other embodiments which may become obviousto those skilled in the art, and that the scope of the present inventionis accordingly to be limited by nothing other than the appended claims,in which reference to an element in the singular is not intended to mean“one and only one” unless explicitly so stated, but rather “one ormore”. All structural and functional equivalents to the elements of theabove-described preferred embodiment that are known or later come to beknown to those of ordinary skill in the art are expressly incorporatedherein by reference and are intended to be encompassed by the presentclaims. Moreover, it is not necessary for a device or method to addresseach and every problem sought to be solved by the present invention, forit to be encompassed by the present claims. Furthermore, no element,component, or method step in the present disclosure is intended to bededicated to the public regardless of whether the element, component, ormethod step is explicitly recited in the claims. No claim element hereinis to be construed under the provisions of 35 U.S.C. '112, sixthparagraph, unless the element is expressly recited using the phrase“means for” or, in the case of a method claim, the element is recited asa “step” instead of an “act”.

What is claimed is:
 1. A communication system, comprising: at least afirst service node; at least a second service node; and at least oneclient station positioned to communicate with the service nodes overrespective first and second channels, the first service node providing afirst part of a use case to the client station and the second servicenode providing a second part of the use case to the client stationsimultaneously with the provision of the first part by the first servicenode, the first and second parts being different portions of the usecase.
 2. The system of claim 1, wherein the first part is a base layerof a multimedia stream and the second part is an enhancement layer ofthe multimedia stream associated with the base layer.
 3. The system ofclaim 2, wherein the client station overlays the enhancement layer ontothe base layer to establish frames of the multimedia stream, each frameincluding data from the base layer and data from at least oneenhancement layer.
 4. The system of claim 1, wherein at least onechannel is bidirectional.
 5. The system of claim 1, wherein bothchannels are bidirectional.
 6. The system of claim 1, wherein theservice nodes are wireless communication system base stations.
 7. Thesystem of claim 1, wherein one of the service nodes is a master node andone of the service nodes is a support node, and the master node directsthe client station to receive the second part from the support node. 8.A method for communication of a single use case to a client station froma service system having at least first and second service resources,comprising: communicating at least a first part of the use case usingthe first service resource to the client station; determining whether todirect the client station to receive a second part of the use case fromthe second service resource, the first and second parts being differentfrom each other in that the second part is not merely duplicative of thefirst part; and in response to the determining act, selectivelydirecting the client station to receive the second part from the secondservice resource.
 9. The method of claim 8, wherein the first and secondparts are received over respective first and second links.
 10. Themethod of claim 8, wherein the first service resource is a first serverand the second service resource is a second server.
 11. The method ofclaim 10, wherein the first server is a first wireless communicationsystem base station and the second server is a second base station. 12.The method of claim 11, wherein the first part is a base layer of amultimedia stream and the second part is an enhancement layer of themultimedia stream.
 13. The method of claim 12, wherein the multimediastream is digitally broadcast.
 14. The method of claim 8, wherein thefirst service resource is a first trunk line and the second serviceresource is a second trunk line.
 15. The method of claim 8, wherein thefirst service resource is a satellite and the second service resource isa terrestrial resource.
 16. The method of claim 15, wherein the firstpart is a base layer of a multimedia stream and the second part is anenhancement layer of the multimedia stream.
 17. A client station,comprising: a first receiver receiving a first part of a use case from afirst service resource; and a second receiver receiving a second part ofthe use case from a second resource simultaneously with reception of thefirst part.
 18. The client station of claim 17, wherein the first andsecond parts do not represent the same data as each other.
 19. Theclient station of claim 18, wherein the first and second parts arereceived over respective first and second links.
 20. The client stationof claim 17, wherein the first service resource is a first server andthe second service resource is a second server.
 21. The client stationof claim 20, wherein the first server is a first wireless communicationsystem base station and the second server is a second base station. 22.The client station of claim 21, wherein the first part is a base layerof a multimedia stream and the second part is an enhancement layer ofthe multimedia stream.
 23. The client station of claim 22, wherein themultimedia stream is digitally broadcast.
 24. The client station ofclaim 17, wherein the first service resource is a first trunk line andthe second service resource is a second trunk line.
 25. The clientstation of claim 17, wherein the first service resource is a satelliteand the second service resource is a terrestrial resource.
 26. Theclient station of claim 25, wherein the first part is a base layer of amultimedia stream and the second part is an enhancement layer of themultimedia stream.
 27. A system, comprising: first service provisioningmeans for providing a first part of a use case to a client station; andsecond service provisioning means for providing a second part of a usecase to the client station, the first and second parts not representingthe same data as each other.
 28. The system of claim 27, wherein thefirst and second provisioning means are first and second trunk lines,respectively.
 29. The system of claim 27, wherein the first serviceprovisioning means is a first server and the second service provisioningmeans is a second server.
 30. The system of claim 29, wherein the firstserver is a first wireless communication system base station and thesecond server is a second base station.
 31. The system of claim 30,wherein the first part is a base layer of a multimedia stream and thesecond part is an enhancement layer of the multimedia stream.
 32. Thesystem of claim 31, wherein the multimedia stream is digitallybroadcast.
 33. The system of claim 27, wherein the first serviceprovisioning means is a satellite and the second service provisioningmeans is a terrestrial provisioning means.
 34. The system of claim 33,wherein the first part is a base layer of a multimedia stream and thesecond part is an enhancement layer of the multimedia stream.